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Across the country, schools have outlined the precautions they’ll take as they reopen their campuses this fall. If and when kids return, schools are planning outdoor “mask breaks” in Denver, one-way hallways in Northern Virginia, and shortened in-person school weeks in New York City, among many, many other safeguards against coronavirus outbreaks.

Included in these reopening plans are a number of measures whose implementation will fall to students themselves. The basic trinity of pandemic safety—distancing, hand-washing, and masking—dictates a new set of cautious behaviors that will be expected of children on school grounds. Kids will also be expected to refrain from many once-normal activities—hugging, sharing toys, trading food at lunchtime, and so on. K–12 students may generally be capable of doing what public-health experts ask, but not all of them, not everything, and not all the time.

Reopening schools certainly poses risks to students, their families, and school staff, but what’s known about children and coronavirus transmission is “still really incomplete,” Ravi Jhaveri, a doctor at Lurie Children’s Hospital of Chicago and a pediatrics professor at Northwestern University’s medical school, told me. Still, he said, the existing scientific evidence indicates that kids under 10 are less likely to contract COVID-19 than teenagers and adults. They also may spread the virus less readily than older people, though researchers don’t know that for certain. (They may learn more about all this as the fall progresses, based on what happens to infection rates in different communities where schools reopen.)

Kids’ imperfect safety compliance likely won’t cause widespread outbreaks, but it will nonetheless present some challenges. Those challenges will be different for different age groups, and older kids may not always be more careful than younger ones.

Unsurprisingly, expectations are lowest for kids under 3—without a grasp on abstract cause-and-effect reasoning, they probably will neither understand nor adhere to public-health measures. Moreover, social distancing “goes against their nature,” Erin O’Connor, an education professor at New York University and a co-founder of the research-based parenting website Scientific Mommy, told me. “Children want to hug each other. They want to play with each other.”

For this reason, day-care safety guidelines focus on things that adults can control. One child-care consultant recently suggested in an interview with NPR that teachers might construct “obstacle course”-style blockades to discourage small kids from wandering over to their peers. Similarly, in Charlottesville, Virginia, one preschool put up temporary fences to establish playground boundaries.

By the time kids are 3 or 4, adults can probably start getting them to follow some rules, perhaps through regular practice or play, even if they can’t grasp the underlying need for them. Also, O’Connor said, “They’re so inquisitive at that stage, and they’re so interested in what the adults in their life are doing.” As a result, they might be inspired to do as the adults do, and wear a mask.

Kindergartners and first graders generally won’t understand the rationale behind various precautions either, but the messaging could start to stick better. “Even younger school-age kids, when we talk to them about trying to sneeze into their elbows, [they] get it,” Jhaveri told me. “I’ve had my kids, when they were younger, chastise [me] for not doing some of those things.”

Second grade roughly marks the beginning of the phase that O’Connor considers to be a sweet spot for compliance: Kids tend to have the mental capacity to understand some of the medical reasons for pandemic safety measures, and often want to emulate the behavior of family members and teachers. Around age 7, they also become a little more altruistic. “You can talk to them about how it’s not only important for them to wear a mask for their own good, but also for their friends’ good, their teachers’, their parents’, their grandparents’,” O’Connor said.

They still won’t be perfect guardians of public health, though. Jhaveri told me about the child of a colleague who “went to school with a Star Wars mask and came home with a Batman mask,” having traded protective gear with a classmate as he might have traded action figures.

Late middle school is when that sweet-spot period comes to an end. While teens will likely have a better understanding of the pandemic’s dangers than younger kids, they might also be more likely to disregard them.

That’s in part because many kids in this age group calibrate their behavior based on what their peers are doing. “So much is about the social scene at that point,” O’Connor noted. They may also be more lax because of how their brains are developing; during adolescence, kids’ mental processing tends to play up the benefits of risky decisions. Thus, a high-school junior might be less likely to practice social distancing than a fifth grader.

Some challenges of getting kids to follow school rules apply at any age. For one thing, kids will break all sorts of rules when they aren’t being watched by an adult. “That’s kind of the nature of kids,” O’Connor said. “But I think a lot of schools have plans in place where they’re going to be monitored really closely.” (Which introduces a separate issue: Teachers will have to play the role of public-health enforcer, which could distract from their teaching responsibilities.)

Kids will also come back to campuses having had very different pandemic habits modeled for them at home—the children of people who don’t take pandemic protocols seriously probably won’t take them seriously either. In particular, O’Connor is concerned that children who don’t abide by those protocols will make fun of those who do. In addition to hurting feelings, that could possibly create pressure for kids to be less cautious.

Many of the country’s students will diligently adhere to schools’ new requirements, while many won’t. But before people blame any students or schools, consider that America’s adults, despite being able to understand the pandemic better than children, haven’t been great at following public-health guidance either.

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